The 24-year-old singer has topped the list of music millionaires under-30 in the Sunday Times' Rich List 2013 for a second consecutive year after amassing an estimated £30 million fortune - a 50 per cent increase on her £20 million wealth in 2012 - thanks to the sales of James Bond theme tune 'Skyfall' and her album '21'.

Cheryl Cole is in second place with £14 million, while Leona Lewis and Katie Melua - who both have a wealth of £12 million each - make up the top five alongside Florence Welch (£9 million) in the female-dominated list.

The first males to feature are JLS singers Marvin Humes, Aston Merrygold, J.B. Gill and Oritse Williams, who have a fortune of £6 million each, behind Jessie J and Charlotte Church, who have amassed £8 million.

Girls Aloud singers Nadine Coyle and Nicola Roberts also have an estimated wealth of £6 million each, as does Duffy - despite her last studio album, 'Endlessly', being released in 2010 - and James Morrison.

Their good friend Ed Sheeran and Emeli Sande - who sang at both the London 2012 opening and closing ceremonies - complete the list with their estimated £5 million fortunes.

What's more, Sir Paul McCartney and his wife Nancy Shevell have the biggest UK music millionaire wealth with an estimated £680 million fortune.

The Beatles legend - who has topped the list of wealthy musicians since 1989 - is followed by Lord Andrew Lloyd Webber (£620 million), while U2's Bono makes up the top three with his estimated £520 million wealth.

Sir Elton John (£240 million) and the combined efforts of David and Victoria Beckham (£200 million) and Rolling Stones frontman Sir Mick Jagger (£200 million) make up the top five.